<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            width: 900px;
            height: 800px;
            background-color: aqua;
        }

        .item {
            float: left;
            width: 300px;
            height: 400px;
            background-color: blueviolet;
        }

        .one {
            height: 800px;
            background-color: red;
        }
    </style>
</head>

<body>
    <div class="box">
        <div class="item one">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
        <div class="item">4</div>
        <div class="item">5</div>
    </div>
</body>

</html>